--------
        In the example below we have a DataFrame with the information about
        planet's mass and radius. We pass the 'mass' column to the
        pie function to get a pie plot.

        .. plot::
            :context: close-figs

            >>> df = pd.DataFrame({'mass': [0.330, 4.87 , 5.97],
            ...                    'radius': [2439.7, 6051.8, 6378.1]},
            ...                   index=['Mercury', 'Venus', 'Earth'])
            >>> plot = df.plot.pie(y='mass', figsize=(5, 5))

        .. plot::
            :context: close-figs

            >>> plot = df.plot.pie(subplots=True, figsize=(11, 6))
        rs